I found this caterpillar on my firecracker plant (Russelia equisetiformis), which is not known to me as a larval food plant. A thread on the butterflies/hummingbird gardening forum yeilded no definitive answers (http://davesgarden.com/forums/t/526777/). Couldn't find the cat last night, so maybe its wandered off to its chrysalis/cocoon stage. I can't find it in my butterfly book. I've e-mailed the "what's this bug" people, but their answer could take a while. The NABA site doesn't offer a way to e-mail photos for ID purposes.

The first two pictures are really tiny and the third picture is not much bigger and is also a little out of focus. It might be more helpful if the photos were in the normal large format for those who have the expertise to assist. That's not me; I just like looking at insects and bugs and learning about them.

If you still have the original photos, take a look at their size - if they're 480 x 640 or larger, post them. Our system will reduce each to a thumbnail, as well as retain a larger (up to 800 x 1,000 - I think) image to display when people click on the thumbnail.

Cnat really tell much from the photos, but have you excluded the tent caterpillar. They eat tree leaves , particularly wild cherry and fruit trees, but just before the cocoon stage wander everywhere, http://www.tent-caterpillar.com/

I haven't excluded the tent cat, but I don't have any wild cherry or fruit trees anywhere near where I found this guy. In fact, I'm not aware of any trees like that on my block. Would a tent cat eat firecracker plants?

It is not a tent caterpillar or sod webworm and it does not look much like any other moth larva. It looks like a butterfly larva to me... similar to a fritillary (but as far as I know they only eat passionflowers). I don't know what eats russelia. Unless it's causing significant damage to the plant I'd leave it alone and see what it turns into!

Sorry, I forgot to post new photos last night. It did not cause significant damage and as it got larger, it did look more and more like some type of fritillary, but then it disappeared. Presumably it's in its chrysalis somewhere... I'll keep looking around, but it may be too late.

Based on the food plant it most likely is a Tropical Buckeye Caterpillar.
Couldn't find any on-line pictures of it for comparison but here is a relative of it (Common Buckeye)http://bugguide.net/node/view/8661/bgpage
The common Buckeye also may use Russelia as food plant